1. Field of Invention
The present invention relates to a memory module assembly and a heat sink assembly configured to be fitted to the memory module assembly, and in particular to a heat sink assembly for radiating heat generated from a fully buffered dual in-line memory module (FBDIMM), a printed circuit board (PCB) of the FBDIMM on which the advanced memory buffer (AMB) package is mounted.
2. Related Prior Art
A memory module may be classified into a single in-line memory module (SIMM) and a dual in-line memory module (DIMM). The SIMM includes a row of memory chips mounted on only one side of the PCB, and the DIMM has two rows of the memory chips mounted on both sides of the PCB respectively.
In order to improve transmission efficiency, a fully buffered DIMM (FBDIMM) has been provided. FBDIMM has a hub, such as an advanced memory buffer (AMB) logic chip that is mounted on the center of the memory module. The AMB chip receives packet signals including a memory command and/or data from an external host (e.g., a memory controller), and provides the received data to respective memory chips. In addition, the AMB chip packetizes data outputted from the memory chips, and provides the packets to the memory controller. In the FBDIMM, signals from external sources are transmitted to the respective memory chips via the AMB chip. Accordingly, all signal lines on which the signals are transmitted are coupled to the AMB chip. Consequently, a large load is concentrated on the AMB chip and high heat may be generated in the AMB chip. High heat reduces the life span of the AMB chip and lowers the operational reliability of peripheral circuits of the AMB chip. Hence, it is advantageous to quickly dissipate away the heat from the AMB chip.
As shown in FIGS. 11 and 12, Taiwan Patent No. 1273688 discloses a memory module integrated mechanism 100 mounted on a motherboard 200, which comprises a plurality of FBDIMMs 110 and a heat sink 120. Each of the FBDIMMs 110 includes a PCB 111, a row of memory chips 112 mounted on the PCB 111, an AMB chip 113 attached to one of the memory chips 112, and a heat sink plate 114. The heat sink plate 114 is attached to the AMB chip 113 and is parallel to the PCB 111 for radiating heat generated from the AMB chip 113. Furthermore, the heat sink 120 is disposed above the FBDIMMs 110 and contacts with each one of the heat sink plates 114 of the FBDIMMs 110. The heat sink 120 comprises a heat dissipating plate 121 and a plurality of clipping members 122 extending from the heat dissipating plate 121. The heat dissipating plate 121 is perpendicular with each one of the PCBs 111 of the FBDIMMs 110. Each of the clipping members 122 extends toward the respective heat sink plate 114 and includes two parallel clipping sheets 122a as depicted in FIG. 12. A top portion of each of the heat sink plates 114 is sandwiched in between the two respective clipping sheets 122a. However, there is not disclosed how the clipping members 122 and the heat dissipating plate 121 are connected in the specification. Generally, the connection may be fulfilled by welding or the like, but requiring much time and work. In addition, the two parallel clipping sheets 122a can only contact the top portion of the heat sink plate 114, which means only little area of the heat sink plate 114 is used for heat transferring to the heat dissipating plate 121. Hence, the heat dissipating efficiency is limited.